Zilliqa Ledger application has a random number generation vulnerability, accounts that have signed 5 or more native transactions may be compromised

Foresight News reports that Zilliqa has disclosed a critical vulnerability in its Ledger application, affecting the Schnorr signature generation for native (non-EVM) Zilliqa transactions. This vulnerability exists in all versions of the Zilliqa Ledger application released between 2019 and 2026. Signs of active exploitation on-chain were detected on July 19, with the root cause confirmed on July 21. The vulnerability allows the temporary random number (nonce) used during signing to be predicted, enabling attackers to recover the signer's private key using only publicly available on-chain data. Zilliqa advises users who have used a Ledger device to sign native Zilliqa transactions to await official guidance and refrain from taking any independent actions for now.

The root cause of the vulnerability lies in the signature program copying the wrong byte range when writing the random number to the buffer, resulting in the top 64 bits of each generated random number being fixed at zero, causing a severe lack of entropy. By leveraging 5 or more affected signatures, attackers can use lattice reduction to recover private keys within seconds. As the affected transactions are permanently recorded on-chain, updating the signature application cannot mitigate this risk and the related private keys must be abandoned. Currently, native transactions have been paused to prevent further loss, and a coordinated remediation plan is in final confirmation. EVM transactions and SDKs such as zilliqa-js, gozilliqa-sdk, and pyzil are not affected.